Triplennamine and dopamine-induced neurogenic vasodilatation
Buylaert, W.; Willems, J.L.
Archives Internationales de Pharmacodynamie et de Therapie 220(2): 327-328
1976
ISSN/ISBN: 0003-9780 PMID: 952588 Document Number: 103107
The effects of antihistaminics on the specific dilatation by dopamine was studied, and the possibility that in the experiments of Brody et al. tripelennamine antagonized the baroreceptor-induced part of the vasodilatation was investigated. Vasodilation in the isolated perfused hindleg of the dog was elicited by histamine administered into the hindleg, i.v. dopamine and noradrenaline (with pressor-effect) and dopamine administered intraaortically (without pressor-effect). A clearcut difference between the ability of tripelennamine to antagonize the vasodilatation induced by pressor doses of dopamine and noradrenaline and the vasodilatation provoked by dopamine given intraaortically was not demonstrated. Some doubt is thrown on the conclusion of Brody et al. that antihistaminics block the neurogenic vasodilatation provoked by high doses of dopamine on the basis of their antihistaminic properties. Much higher doses of tripelennamine were required to antagonize the vasodilatation provoked by dopamine and noradrenaline than to antagonize the direct vasodilatation by histamine, and the neurogenic vasodilatation provoked by dopamine given intraaortically was blocked in a noncompetitive way.